1. Field of the Invention
The present invention is in the field of sports rackets, especially tennis rackets, and relates to improved vibration and shock absorbancy.
2. Description of the Prior Art
U.S. Pat. No. 4,057,250 describes a racket which has weight means which moves transverse to the plane of the racket stringing to provide inertial rebound deadening when the racket strikes a ball. A hollow container is mounted adjacent to the bow portion and is attached to transmit forces on the container directly to the racket, including a quantity of heavy, discrete, shot-like particles partially filling the container without substantial restraint in opposite dirtections along an axis extending generally along the intended direction of swing of the racket and generally perpendicular to the racket plane.
U.S. Pat. No. 4,364,564 discloses a shock absorber which has the same objective as the present invention but accomplishes it by filling a hollow wrist housing with a high density liquid such as mercury. This supposedly absorbs the vibrational effects of hitting the tennis ball.
The traditional wood sports rackets have been almost completely replaced by lighter aluminum rackets, or graphite-, fiberglass-, or ceramic-reinforced composite rackets. Aluminum and composite rackets are much more flexible than wood rackets and as a result have an undesirable tendancy to tramboline the ball. Some of this tendancy can be controlled by using a heavier guage aluminum. Composites such as graphite or ceramic are lighter, stronger, and stiffer than aluminum, and so less energy goes into flexing the racket and more goes into powering the ball. In spite of this advantage, excess energy is transferred via vibration or shock motion to the player's arm, resulting in "tennis elbow" in many cases. According to many experts, tennis elbow is caused in great part by the vibration and shock transmitted from the sports racket to the player's hand and continuing up the forearm to the elbow.